The present invention is directed to a roof window with a locking device for locking the sash in open positions relative to the casing, and an opening device provided in the form of at least one spring arm which is disposed at a right angle to the window casing when the roof window is closed, which supports the window sash on the casing in its open position.
Roof windows have to be held in the open position so that they do not return to the closed position or open further because of their weight or under the action of the wind. Until now, rods capable of being hooked or clamped as well as built-in resistance to movement have been proposed as solutions for this problem. However, these solutions developed for window hatches are not satisfactory for use in house roof windows.
Therefore, German Offenlegungschrift 2 422 328 proposes the arrangement of two supporting levers which hold the opened window in its open position by spring force. These supporting levers with springs are mounted on the window sash and move on rollers in guide rails on the window frame, and catch plates hold the window in a desired pivoted position. However, this window is not held securely, particularly in the case of high winds. The holding positions are limited to the catches, and the catches lead to jerky motion when the window is opened and closed.
It is an object of the invention to provide a novel roof window with locking device which guarantees secure holding of the window sash in each open position.